Air blower



April 2, 1957 SCHLUMBOHM AIR BLOWER Filed April 20 1955 INVENTOR.

United States Patent AIR BLOWER Peter Schlumbohm, New York, N. Y.

Application April 20, 1955, Serial No. 502,696

2 Claims. (Cl. 230-128) The invention refers to a centrifugal blower in which the air leaves the centrifuging impeller through a 360 nozzle at the periphery of the impeller. Such blowers are used for supplying air to burners, motors (superchargers) and as Ventilating fans. In such apparatus it is usual to surround the impeller with a cowl for collecting the air coming out of the nozzle and for directing the air in a tangential flow. The invention aims at a special cowl design and at the arrangement of the cowl in relation to the impeller and its driving means.

The invention is illustrated by way of example in Fig. l-Fig. 4 of the accompanying drawings.

Fig. 1 shows, partly in view, partly in vertical cross section and partly broken away, a side view of a portable fan as used for breathing comfort.

Fig. 2 is a side view of Fig. 1 and a front view of the fan.

Fig. 3 is a top view of the fan shown in Fig. 1 and Fig. 2.

Fig. 4 illustrates a detail.

As shown in Fig. 1 the impeller 1 is surrounded by a cowl 5, which has two intake openings 6, 7 and an exhaust opening 8.

The casing of the blower has an annular bottom wall and oppositely disposed side walls which extend from the bottom wall towards the center of the casing, where they terminate in a pair of central eyes 6, 7. Each of these two side walls has an inwardly oppositely disposed projecting surface which forms an annular restriction 12 therebetween, intermediate between the bottom wall and the central eyes. A motor 2 is mounted on a support 3 and a base 4. The base 4 is also the support for the casing 5 held by bolt 9. The arrangement is such that the shaft of the motor is coaxial with said central eyes and extends into the casing 5. The shaft carries the impeller 1. The impeller is disc-shaped and extends from said shaft mounting outwardly to a 360 peripheral discharge edge which terminates at the zone 12 of minimum restriction between said side walls. Air passing through the zone 12 of minimum restriction is compressed and collected in the peripheral zone of the casing and this section of the casing can be tapped for discharging the compressed air.

I found that a very advantageous structure for tapping this compressed air is a slot 8 in the bottom wall of the released air. The length of that slot is limited to a fraction of the circumference of the bottom wall as otherwise there would be no walled space left for compressed air. Otherwise its actual length is not critical as it depends on the intended effect. Either one wants to release much air with little pressure or a small quantity of air with the maximum pressure. For the purpose of a room ventilator, I found a length corresponding to a sector of 75 of the bottom wall practical. To discharge the air through a slot in the bottom wall produces a well-defined, highly directional beam of air.

While liquid pumps have been known which impel fluid into a 360 Venturi, the known structures were based on said Venutri effect alone. In the present invention there is a very definite additional pumping effect created by the cooperation of the side walls which, on each side of the disc-shaped impeller, extend from the Venturi restriction towards the axial zone. Between the one surface of the impeller and the inside surface of the one wall, and between the other surface of the impeller and the inside surface of the opposite side wall, a friction pump effect is created. A vacuum is produced in these two spaces. Air is sucked into this vacuum through the central eyes 6, 7 and is centrifuged towards the zone 12, thus feeding the Venturi very efficiently. The Venturi 12, allowing only one-way flow, then forms a check valve which prevents backfiring of the air compressed in the peripheral collecting space of the casing 5.

A fan of these features has an unusual depth of penetration, shooting a well defined vector of high speed air in a laminated flow.

I claim as my invention:

1. An air blower comprising a casing having an annular bottom wall and oppositely disposed side walls extending from said bottom wall and terminating in a pair of central eyes, each of said side walls having an inwardly oppositely disposed projecting surface forming an annular restriction therebetween, and intermediately between the bottom wall and the central eyes; a shaft mounted coaxial with said central eyes, an impeller mounted to said shaft and coaxial with said central eyes, said impeller comprising a disc extending from said shaft mounting outwardly to a 360 peripheral discharge edge, said edge terminating at the point of minimum restriction between said side walls and a discharge opening in the peripheral zone of said casing beyond said minimum restriction.

2. An air blower as claimed in claim 1, in which said discharge opening is a slot in the bottom wall of said casing.

References Cited in the file of this patent UNITED STATES PATENTS 860,465 Hancock et al. July 16, 1907 1,556,203 Clarage Oct. 6, 1925 1,611,857 Feinberg et a1. Dec. 21, 1926 2,641,404 Schwarz June 9, 1953 2,706,016 Schlumbohm Apr. 12, 1955 FOREIGN PATENTS 28,018 Great Britain of 1906 161,796 Great Britain Apr. 21, 1921 

